With reference to FIG. 1, the prior art way for combining the heat conductive tubes and heat dissipating unit are illustrated. Firstly, the seat 51 is welded to the heat conductive tubes 50. A plurality of fins are engaged to a plurality of heat conductive tubes 50 by punching one by one. In the welding process, welding material is coated upon the welding surfaces of the heat conductive tubes 50 and the seat 51. Then they are placed in a vacuum furnace for heating so that the welding material will permeate into the combining surfaces. After cooling, the welding process is completed. However, the process is long and it is very complicated for controlling the time sequence. In the process, poisonous harmful material will generate, which is harmful to human bodies and environment. The welding material contains lead and other heavy metals. Thereby, the process is not suitable to be used. Furthermore, the punching process is performed one by one. The combination of the fins 52 and the heat conductive tubes 52 will be affected by the vibration of the punching machine so that gaps are formed between the fins 52 and the heat conductive tubes 50. Thereby, heat convention ability is reduced and thus the yield ratio is decreased.
To improve above mentioned defect, a novel method is disclosed. With reference to FIG. 2, the heat conductive tube 60 passes through one side of the fin 61. Then it is placed on a top of a bottom plate 62 of a central processing unit (not shown). The heat conductive tube is bent by a punching unit 62 and is then buckled. Thereby, heat of the central processing unit transfers through the bottom plate 62 to the heat conductive tube 60 and the fin 61 and thus disperses out from the fin 61. However, the heat conductive tube 60 is buckled so that gaps are formed between the heat conductive tube 60 and the fin 61 or the bottom plate 62. As a result, heat resistance is high and heat convention is low and thus heat dissipation is reduced. The heat conductive tube 60 has no effect in heat dissipation.